Uncreped throughdried tissue sheet manufacturing methods are capable of extremely high production rates when producing tissue sheets. Softness is achieved by proper selection of fibers, layering, rush transfer, high-topography throughdrying fabrics and heavy calendaring to produce the resulting tissue sheet. Much of the bulk realized on the tissue machine is lost during calendaring. By comparison, conventional creped throughdried tissue sheets are generally soft but lack the bulk, acceptable lint levels and processing flexibility associated with uncreped throughdried processes.
In the manufacture of rolled, creped tissue products such as bathroom tissue and paper towels, a wide variety of product characteristics must be given attention in order to provide a final tissue product with the appropriate blend of attributes suitable for the product's intended purposes. Improving the softness of tissues is a continuing objective in tissue manufacture, especially for premium products. Softness, however, is a perceived property of tissues comprising many factors including thickness and smoothness, that is, low surface-roughness, and flexibility. Generally, higher softness is perceived with high basis weight webs due to the increased thickness of the tissue sheet. In turn, as the basis weight of the tissue sheet is increased, achieving high sheet bulk becomes more challenging since much of the bulk of the tissue structure is achieved by molding of the embryonic tissue web into the papermaking fabric and this bulk is decreased by increasing the basis weight of the sheet. Thus, there remains a need for creped tissue sheets having low surface-roughness and improved bulk at low basis weights.
When the creped tissue sheet is formed into a rolled product, the tissue sheet tends to lose a noticeable amount of bulk due to the compressive forces that are exerted on the base web during winding and converting. As such, a need currently exists for a spirally wound tissue product that can maintain a significant amount of roll bulk, sheet bulk and sheet softness even when the product is wound to produce a roll having consumer desired firmness. A firm roll conveys superior product quality and a large diameter conveys sufficient material to provide value for the consumer. From the standpoint of the tissue manufacturer, however, providing a firm roll having a large diameter is a challenge. In order to provide a large diameter roll, while maintaining an acceptable cost of manufacture, the tissue manufacturer must produce a finished tissue roll having higher roll bulk. One means of increasing roll bulk is to wind the tissue roll loosely. Loosely wound rolls however, have low firmness and are easily deformed, which makes them unappealing to consumers. Hence, there also remains a need for rolled, creped tissue products to have high roll bulk and good roll firmness.